/*
 *	
 * Copyright (c) 2016 Cisco Systems, Inc.
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 
 *   Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * 
 *   Redistributions in binary form must reproduce the above
 *   copyright notice, this list of conditions and the following
 *   disclaimer in the documentation and/or other materials provided
 *   with the distribution.
 * 
 *   Neither the name of the Cisco Systems, Inc. nor the names of its
 *   contributors may be used to endorse or promote products derived
 *   from this software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

/**
 * \file addr.c
 *
 * \brief network address functions (IPv4 only for now)
 */

#include "addr.h"

/**
 * \fn unsigned int ipv4_mask (unsigned int masklen)
 * \param masklen length of the subnet mask
 * \return ipv4 mask
 */
unsigned int ipv4_mask (unsigned int masklen) {
  unsigned char tmp = 0;
  unsigned int i, j, bytes, bits = 0;
  unsigned int m = 0;
  unsigned char *mask = (unsigned char *)&m;

  bytes = masklen/8;
  bits = masklen - bytes*8;
  
  for (i=0; i<bytes; i++) {
    mask[i] = 0xff;
  }
  tmp = 128;
  mask[i] = 0;
  for (j=0; j<bits; j++) {
    mask[i] |= tmp;
    tmp >>= 1;
  }

  return m;
}

/**
 * \fn unsigned int addr_mask (unsigned int addr, unsigned int masklen)
 * \param addr ipv4 address
 * \param masklen length of the subnet mask
 * \return ipv4 address mask
 */
unsigned int addr_mask (unsigned int addr, unsigned int masklen) {
  struct in_addr mask;

  mask.s_addr = ipv4_mask(masklen);
  return mask.s_addr & addr;
}
